如何從一組物件中，通過一個或多個不同的屬性名稱/物件鍵對每個任務進行分組、合并和聚合值？

我有一個物件陣列，如下所示。

我想將具有相同bank, gender,age和的那些分組state在一起。

我想分別將它們的和加在一起，并計算每個組。（不包括在輸出中）depositAmountwithdrawalAmountuser

示例陣列

[{
    "bank": "bank1",
    "user": "u1",
    "depositAmount": 12,
    "withdrawalAmount": 33,
    "gender": "male",
    "age": 38,
    "state": "Arizona"
},
{
    "bank": "bank1",
    "user": "u2",
    "depositAmount": 25,
    "withdrawalAmount": 44,
    "gender": "male",
    "age": 38,
    "state": "Arizona"
},
{
    "bank": "bank2",
    "user": "u3",
    "depositAmount": 10,
    "withdrawalAmount": 0,
    "gender": "male",
    "age": 38,
    "state": "Florida"
}]

預期產出

[{  
    "bank": "bank1"
    "depositAmount": 27,
    "withdrawalAmount": 77,
    "gender": "male",
    "age": 38,
    "state": "Arizona"
    "count": 2
},
{  
    "bank": "bank2"
    "depositAmount": 10,
    "withdrawalAmount": 0,
    "gender": "male",
    "age": 38,
    "state": "Florida"
    "count": 1
}]

uj5u.com熱心網友回復：

這個問題的一個通用解決方案是為“它分組、合并和聚合”任務實作一個可配置的減速器功能。

為了滿足 OP 的要求，提供了一個相應定制的自定義收集器物件作為reduce-method 的初始值。

通用 reducer 期望提供 a createKey、 acreateMerger和一個aggregate函式以及一個Mapbasedlookup和一個空result陣列，后者一旦運行 reduce 任務，將保存所有分組/合并和聚合的物件。

至于OP的具體要求，提供的功能是......

• 歐...

  “我想將具有相同bank, gender,age和的人分組state在一起。”

  • createKey: ({ bank, gender, age, state }) => [bank, gender, age, state].join('_')

• 歐...

  “我想分別將它們的和加在一起，并計算每個組。（不包括在輸出中）。”depositAmountwithdrawalAmountuser

  • createMerger: ({ bank, gender, age, state }) => ({ bank, gender, age, state, count: 0, depositAmount: 0, withdrawalAmount: 0 })

  • aggregate: (merger, { depositAmount, withdrawalAmount }) => { merger.count; merger.depositAmount = depositAmount; merger.withdrawalAmount = withdrawalAmount; }

function groupMergeAndAggregateGenerically(collector, item) {
  const {
    createKey, createMerger, aggregate,
    lookup, result = [],
  } = collector;

  const key = createKey(item);
  let merger = lookup.get(key) ?? null;

  if (merger === null) {
    merger = createMerger(item);

    lookup.set(key, merger);
    result.push(merger);
  }
  aggregate(merger, item);

  return collector;
}

const sampleData = [{
  "bank": "bank1",
  "user": "u1",
  "depositAmount": 12,
  "withdrawalAmount": 33,
  "gender": "male",
  "age": 38,
  "state": "Arizona"
}, {
  "bank": "bank1",
  "user": "u2",
  "depositAmount": 25,
  "withdrawalAmount": 44,
  "gender": "male",
  "age": 38,
  "state": "Arizona"
}, {
  "bank": "bank2",
  "user": "u3",
  "depositAmount": 10,
  "withdrawalAmount": 0,
  "gender": "male",
  "age": 38,
  "state": "Florida"
}];

// OP: I would like to group those with the same
// `bank`, `gender`, `age`, and `state` together.
const createKey = ({ bank, gender, age, state }) =>
  [bank, gender, age, state].join('_');

// OP: I'd like to sum their `depositAmount` and
// `withdrawalAmount` together, respectively, and
// `count` each group as well. (`user` is excluded in the output).
const createMerger = ({ bank, gender, age, state }) => ({
  bank, gender, age, state, count: 0, depositAmount: 0, withdrawalAmount: 0,
});
const aggregate = (merger, { depositAmount, withdrawalAmount }) => {
    merger.count;
  merger.depositAmount  = depositAmount;
  merger.withdrawalAmount  = withdrawalAmount;
};

const { result: mergedData } = sampleData
  .reduce(groupMergeAndAggregateGenerically, {
    createKey,
    createMerger,
    aggregate,
    lookup: new Map,
    result: [],      
  });

console.log({ mergedData });

.as-console-wrapper { min-height: 100%!important; top: 0; }

標籤：javascript 数组 目的 合并 分组

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